Start by adding water and sugar into a small pot or medium size sauce pan on medium heat.

Wash your blackberries thoroughly (or whatever fruit you are using) and then add them to the water and sugar mixture.

Let the blackberry syrup mixture simmer for 10 minutes and then remove from heat.

When it's had a few minutes to cool, give it a taste to determine whether you want to add a squeeze of lemon to brighten up the flavor and push down a bit of the sweetness. This is really just a preference thing and may also depend on how fresh / ripe the fruit that you're using.